Is working as a maintenance technician for electronic devices (such as televisions, recorders, and satellite receivers) permissible or forbidden, knowing that they are often used in ways that displease Allah?

It is permissible to sell and repair devices if you are certain or have a strong presumption that they will be used for lawful purposes. It is not permissible if you are certain or have a strong presumption that they will be used for unlawful purposes. This includes the prevalence of unlawful use of devices, even if the buyer's intention is unknown. It is more cautious to refrain from selling or repairing them if the two possibilities are equal or if the intention of use is unknown.